Process of making lenses



Dec. .15. 1 925- 1,566,051

4 H. W. HILL El AL PROCESS OF MAKING LENSES xFiled Aug. 1922 3 INVENTORS H-W- mu. E. a. TILLYER ATTORNEY$ Patented Dec. 15, 1925.

UNITED STATES PATENT OFFICE.

HARRY W. HILL AND EDGAR D, TILLYER, Q13 SOUTHBRIDGE, MASSACHUSETTS, AS-

SIGNORS T0 AMERICAN OPTICAL COMPANY, OF SOUTHBRIDGE, MASSACHUSETTS, A VOLUNTARY ASSOCIATION OF MASSACHUSETTS.

PROCESS OF MAKING LENSES.

Application filed August 2, 1922. Serial No. 579,192.

T 0 all 10 homit play concern Be it known that we, IIisnnv IV. HILL and EDGAR D. TILLYER, citizens of the United States, residing at Southbridge, in the county of Worcester and State of Massachusetts, have invented certain new and useful Improvements in Processes of Making Lenses, of which the following is a specification.

This invention relates to improvements in the manufacture of lenses and more particularly to a process used in the grinding of ,lenses to eliminate prism c'lfects and at the same time determine the proper thickness of the lenses to be ground.

Heretofore in the manufacture of lenses especially lenses of the smaller type the strap thickness of the lens has been used to determine the proper thickness for the entire lens, but one of the main objects of my invention is the provision of a new and improved lens blank and process for manufacturing the same whereby indicating points are established upon the body of the lens for the purpose of determining the proper thickness to which the lens is to be ground.

A further object of the invention is the provision of a lens blank and process of forming the same wherein the indicating points may be disposed at right angles to each other to compensate for the tilting of the lens during thegrinding operation to thus assure the even grinding of the lens thruout.

With the above and other objects in view the invention consists in the novel features of construction, the combination and arrangement of parts herein-after more fully set forth, pointed out in the claims and shown in the accompanying drawings, in which V Figure I is a plan view of a lens blank showing the application of our invention.

Figure II is a front elevation of a drill used in connection with our invention, parts of the same being illustrated in cross section.

Figure III is a longitudinal sectional view on the line IIIIII of Figure I.

Figure IV is a side elevation of a lens grinding lap with one of our improved lenses arranged thereon illustrating the grinding of the lens in an uneven manner.

Figure V is a similar view showing how the lens can be ground evenly thruout its concave surface.

Figure VI is a side elevation showing the manner in which the lens isattached to the block.

Figure VII is a plan view of the same, and

Figure VIII is a side elevation of a lens illustrating the close fitting of the strap after the lens has been ground in accordance with our invention.

In the carrying out of our invention We provide a drilling machine which in the pres ent instance comprises a base member 1 having an angular portion 2 forming a seat for the lens 3 adapted to be placed thereon to be operated upon by the drills. The drills 4: are each rotated thru the medium of a shaft 5 which has a pinion 6 at its upper end adapted to mesh with a gear 7.

In order to impart movement to the drilling machine a pulley 8 is mounted above the gear 7 and connected to any suitable source of power by means of a belt 9.

The lower ends of the shafts 5 are pro vided with spaced sleeves 10 arranged upon opposite sides of the ends ofthe arm 11. This arm 11 is provided with a sleeve 12 at its intermediate portion and fitted within this sleeve is an adjusting pin 14 having an adjusting screw 15 mounted thereon whereby the drill members 4 may be adjusted vertically to determine the thickness or depth of the indicating recesses to be placed in the lenses, so as to assure the proper amount of grinding.

In Figures I and III we have illustrated a lens provided with spaced recesses 16 which are drilled into the lens blank the proper depth so that when the concave surface of the lens 3 is ground down so as to eliminate these recesses the predetermined thickness of the lens to constitute a finished lens will be provided.

Attention is called to the fact that in the ues for the distance between the recesses will be sufiicient for the depth of the recesses will vary with the different series. The lenses are grouped into series of lenses, each lens within a series having the same base curve so that all lenses with the same base curve will be provided'with the same depth of recesses. In this manner a predetermined strap thickness is presented in all of the finished lenses so that no difiiculty will arise when the lens straps are associated with the lenses for use.

It will be apparent that by marking lenses in this manner, the operator may readily determine whether or not a lens is being groan d properly attention being called to Figure IV wherein one side of the lens is being ground considerably faster than the other side of the lens, so that the operator may readily adjust the position of the lens for the proper grinding.

It will be apparent that while we hare shown and described the use of only two recesses, four such recesses may be used equally as well to con'ipensate for the tilting of the lens, during the grinding operation in various directions so that the proper thickness of the lens may be readily and properly ground.

In order to retain the lens in their proper positions while being secured to a concave block, a. substantial holder or retainer is provided comprising a cross piece 17 having arms 18 at its ends which are provided with forks 19 adapted to be fitted over the guide arms 20 of thelap :21. From this it will be apparent that when the forks 19 are fitted over the arms 20 the contact points 22 carried by the bar 17 will have their lower ends fitted into the drill openings or recesses l6 in the lens whereby to securely retain the lens in its )roper position while being titted and adhered to the lap 21.

In FigureVIlI I have illustrated a. finished lens with a strap 23' fitting over the edge of the lens in its proper position. It will. be noticed from this figure that the strap fits snugly over the edge of the lens due to the grinding of the lens to the proper thickness said grinding operation being carried out by the use of our improved process for centering lenses wherein a lens blank is recessed to the proper depth, the depth de pending upon the lens series from which the lens is taken, and then removing that portion of the blank from the outer end of the recess to the inner end thereof.

Particular attention is called to the fact that the lenses may be centered both ways prior to grinding and polishing the finished lens by arranging the lens in its proper position beneath the drill points '-l-.

What we claim is l. A process of the class described including the drilling of spaced recesses in one face of a lens blank and then grinding the lenses to remove the surface of the same to the inner ends of the recesses.

2. The process of forming lenses, consistin in surfacing one face of a blank and forming in the opposite face recesses extending in predetermined relation to the tinished surface. and subsequently removing' the material on the opposite face of the blank to the points determined by the bottoms of the recesses.

23; The process of for-idling; lenses consisting in forming recesses in one surface of a lens blank to a predetermined depth. said recesses being arranged in spaced relation at diametrically opposed points. and wherein the distance between the non-recessed surface and the bottoms of the recesses will indicate the thickness to which the lens blank is to be surfaced to produce a finished lens of re quired characteristics.

EDGAR l). TILL "Ell. HARRY V. HILL.

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